1. Technical Field
The present disclosure relates to an image processing device, a printing system, and a control method of an image processing device.
2. Related Art
Systems in which a control device (host device) and a printing device (printer) communicate with each other are known from the literature. See, for example, JP-A-2006-11809. To control the printer, the control device generally sends control-related data to the printer. The printer then executes a process based on the data received from the control device.
Methods of using image data that represent the differences between images in order to reduce the amount of data when sending and receiving plural images are also known from the literature. See, for example, JP-A-2012-44478. The method disclosed in JP-A-2012-44478 compares two images, extracts difference rectangles containing a desired number of dots, and obtains a difference image by merging the difference rectangles.
When sending data from the control device to the printer in this type of system, reducing the amount of data that is sent from the control device to the printer is desirable in order to improve communication efficiency.
In the method that extracts rectangles showing the difference between two images as described in JP-A-2012-44478, detailed differences can be extracted with little loss by defining small rectangles, but increasing the number of rectangles increases the total required processing time. Increasing the size of the extracted rectangles reduces the number of rectangles and therefore shortens the processing time, but also increases waste because a large number of dots that do not require difference extraction are contained in the extracted rectangles. The desired effect of reducing the amount of data by extracting the differences between the images is therefore also lost. A method enabling both reducing the amount of data and accelerating processing in a process that uses image difference data to reduce the amount of data is therefore desirable.